Miniaturization and improvement in energy efficiency of hybrid automobiles or electric automobiles have led to a demand for miniaturization and improvement in efficiency of vehicle components including power converters used in the hybrid automobiles or the electric automobiles.
A DC bus bar that is mounted on the power converter and transmits a DC current can contribute to the miniaturization of the power converter and a reduction in parasitic inductance of the DC bus bar when an interval between positive and negative electrodes is made as short as possible. This can bring about a reduction in loss of a switching element used in the power converter. In other words, conversion efficiency of the power converter can be improved.
In this case, insulation between the positive and negative electrodes of the DC bus bar needs to be ensured in order to shorten the interval between the positive and negative electrodes of the DC bus bar. PTL 1 describes an invention to cause a plurality of DC bus bars to overlap each other and cast resin into an interval between the bus bars to save a space and ensure insulation.